| Name | neptunium |
| Synonyms | neptunium neptunium atom |
| CAS | 7439-99-8 |
| EINECS | 231-108-8 |
| Molecular Formula | C6H6NO2 |
| Molar Mass | 124.11734 |
| Density | 20.45; d 19.36 |
| Melting Point | 637° |
| Boling Point | bp 4174° |
| Water Solubility | soluble HCl [HAW93] |
| Solubility | Soluble in DMSO (>25 mg/ml) |
| Appearance | silvery metal |
| Color | Off-white |
| Storage Condition | -20°C |
| Stability | Stable for 1 year from date of purchase as supplied. Solutions in DMSO may be stored at -20°C for up to 1 month. |
| EPA chemical information | Neptunium (7439-99-8) |